1. Field of the Invention
This invention relates to an improved throat plug assembly for a dispensing system, which may be either an open loop or closed loop dispensing system, and more particularly to a dispensing system for dispensing corrosive liquid chemicals or dangerous medical liquid products which are typically drawn from the upper end of a container, such as a bottle or the like, to a mixing machine or the like. In the instant invention, the container is inverted with the liquid product gravity flowing from the lower end thereof. Further, the dispensing system of this invention provides a means for venting the container during shipment or storage in those situations where the liquid within the container requires venting. Even more particularly, this invention relates to a plastic spring-loaded valve within the throat plug assembly. In the preferred embodiment, the retainer at one end of the throat plug assembly and the plastic spring are of one-piece molded construction.
2. Description of the Related Art
Corrosive liquid chemicals and dangerous medical liquid products are typically contained in a container such as a bottle or the like and are frequently dispensed therefrom to a mixing machine. Normally, a cap is placed on the bottle with a dip tube extending therefrom downwardly into the interior of the bottle for drawing the liquid upwardly thereinto. Normally, a dispensing tube extends from the cap to a mixing machine or some other piece of equipment which creates suction in the dispensing tube to draw the liquid from the interior of the bottle. In some prior art devices, when the suction or vacuum is removed from the dispensing tube, backflow may occur. Further, when the cap is removed from the bottle, backflow from the dispensing tube may also occur. Additionally, when the cap is removed from the bottle, liquid residue in the bottle may spill therefrom. Additionally, the conventional prior art systems normally do not prevent the re-use of the bottle which is prohibited in some cases. Yet another disadvantage of the prior art is that a reliable and efficient venting means for the bottle is not normally provided for relieving vacuum pressure from within the bottle. The system of Applicant's U.S. Pat. No. 6,968,983 solved the problems associated with the prior art devices or systems.
While the system of Applicant's U.S. Pat. No. 6,968,983 works extremely well when the container is in its normal upright condition, the system may not perfectly function when the container of said patent is inverted. When the container or bottle of the said patent is inverted, the liquid in the container is drawn or discharged from the normal upper end of the container but which is the lower end of the container in the inverted position. In such a position, the venting membrane, which would normally permit ambient air to replace the liquid in the container as the liquid is discharged from the container, may become “clogged”due to the liquid coming into contact therewith and crystallizing thereon. If air is not permitted to enter the container as the liquid is drawn therefrom, a partial vacuum is created in the upper end of the inverted container which will interfere with the discharge of the liquid therefrom.
In Applicant's earlier throat plug assemblies which were an important part in the dispensing and/or dosing systems, a metal spring was utilized to yieldably maintain the valve in the throat plug assembly in a closed position with a separate cap or retainer holding the metal spring in position. An ecological problem exists with the use of a metal spring in an otherwise completely recyclable plastic throat plug assembly since the metal spring must be removed from the throat plug assembly which is being discarded to enable the other plastic components of the throat plug assembly to be recycled. In many cases, the discarded throat plug assemblies were simply thrown into the trash due to the cost of removing the metal spring from the throat plug assembly. Further, in Applicant's earlier throat plug assemblies, the metal spring and the retainer thereof were separate pieces or parts thereby requiring separate manufacture and separate assembly into the throat plug assembly.